Brush-holder for dynamo-electric machinery.



A. AICHELE.

BRUSH HOLDER FOR DYNAMO ELECTRIC MACHINERY.

APPLICATION FILED MAY 4, 1912.

1,102,11 9; Patented June 30,1914.

M J/%% a UNITED STATES PATENT OFFICE.

ALBERT .AICHELE, OF BADEN, SWITZERLAND, ASSIGNOR T0 AKTIENGESELLSCHAFTBROWN, BOVERI & CIE., OF BADEN, SWITZERLAND.

BRUSH-HOLDER FOR DYNAMO-ELECTRIC MACHINERY.

To all whom it may concern:

Be it known that I, ALBERT AIoHELn, director, a citizen of the SwissRepublic, of Baden, Switzerland, have invented certain new and usefulImprovements in and Relating to Brush-Holders for Dynamo-ElectricMachinery, of which the following is a specification.

. This invention relates to brush holders for electrical machines.

Heretofore efforts have been directed to give carbon brushes forelectrical machines as firm and as long a support as possible to enablethem to maintain their position relatively to the commutator. Thisprinciple leads to long and comparatively heavy carbons. and brushholders, and owing to expansions due to heat or to other reasons seizingis liable to occur. Moreover the commutator must be perfectly round andbe exactly centered if the good contact of the carbons with longsupports is to be maintained.

The object of the present invention is to provide an improved brushholder efficient in action and free of the disadvantages asto weight andotherwise referred to above.

The invention consists in a brush holder in which the carbon or likebrush as well as being free to follow irregularity in the commutatorsurface is also free for a certain distance to move at right anglesalong this surface.

The invention also consists in a brush holder in which a carbon or likebrush is embraced by anarrow frame loosely fitting the carbon, a springconnection being pro vided to permit motion in the direction of thecommutator but normally to maintain the brush in its mid position.

Referring to the accompanying drawings which illustrate one manner ofcarrying the invention into effect: Figure 1 .shows an elevation,andFig. 2 a plan of one construction of brush holding mechanism. Fig. 3shows certain of the parts illustrated in Fig. 1 with the springcooperating with the brush in its inoperative position and also (indotted lines) in the position which it occupies when the brush is worndown. Fig. 4: shows a perspective view of a brush fitted with a modifiedform of spring.

LThe'form of the invention illustrated includes a brush holder theterminal piece a of which is mounted on' the brush rod (notSpecification of Letters Patent.

Patented June 30, 1914..

Application filed May 4, 1912. Serial No. 695,169.

pulled downward by means of a. spiral spring 7. The lever 6 does notbear directly onthe 'brush d but through the medium of a sprlng rod orwire 9 hinged at one end to the lever 0 while its other en'dis attachedto a plate It pressing on the brush and supported thereon,

The spring rod g can obviously be replaced by several such members whileinstead of it one or more plate springs, spiral springs, 01' others maybeused so long as they are arranged to restore the brush to its normalposition whenit is displaced therefrom.

The spring may also be directly attached to the carbon, so that theplate It is eliminated. I

In the modification shown in Fig. 4 the brush a is provided with'a flatplate spring 5 which is adapted to be pivotally connected to the lever 6shown in Figs. 13. In this form the plate spring is secured directly tothe brush a thereby eliminating the plate It, though the latter may beretained if desired.

The particular construction shown in the drawings are given by way ofexample and modifications in' the details may be made as desired.

It will be noted'that the main feature of the invention is the springpiece 9 which same to the normal position, while in a radial directionit is practically inelastic and allows the spring f to exert its fullpressure. Thus the brush is under the action of at least two springs oneof which exerts as usual contact pressure in a direction normal to thecommutator while the other operates n a plane at right angles thereto.There 1s thus obtained a similar effect as if instead of carbon, anelastic material had been used. Further, this spring can be so formedthat it counteracts an uneven wearing of thebrush. If the wear be notuniform the spring rod causes the pressure to become higher on the lessworn edge, while at the most worn edge the pressure diminishes. Aninclined position of the carbon which apart from the spring 9 ispossible owing to the narrowness of the frame, can not therefore takeplace and the'axis of the carbon brush always remains radial since theaction of the springs opposes any other position. On the other hand thecarbon is able'exactly to follow any worn place and eccentricity of thecommutator, always remaining in contact with the surface of the samesince its mass may be kept small owing to the narrow and light guidingframe.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is 1. In dynamo electric machinery incombination a brush means loosely encircling the brush, a lever, aspring connecting said lever and said means together with a memberconnecting the lever and the brush rigid in the direction of contactpressure but flexible in the direction at right angles thereto; as setforth.

2. In dynamo electric machinery in combination a brush a bracket, anelement rigidly attached to said bracket and loosely encircling thebrush, a lever pivoted to the bracket, a spring member connecting thelever and the brush rigid in the direction of contact pressure butflexible in the direction at right angles thereto and a spiral springconnecting a pointbetween the pivot and said end of said lever with saidencircling means as set forth.

3. In dynamo electric machinery in combination a brush means looselyencircling the brush, a lever, a spring connecting said lever and saidmeans together with a spring wire connecting the lever and the brushrigid in the direction of contact pressure but flexible in the directionat right angles thereto; as set forth.

5. In dynamo electric machinery in combination a brush, means looselyencirclin the brush, a lever and a spring rod inserted between the leverand the brush substantially coinciding with the axis of said brush; asset forth.

5. In dynamo electric machinery in com? bination a brush, a narrow frameencircling said brush with slight clearance on all sides, a springtending to force the brush in one direction and a further spring tendingto force the brush in a direction at right angles thereto ondisplacement, said further spring being substantially rigid in thedirection of pressure "of the first spring; as set forth.

6. In dynamo electric machinery in com bination a brush, a bracket,'anelement rigidly attached to said bracket and encircling said brush onallsides with a slight and substantially uniform clearance, a lever pivotedto the bracket, a spiral spring connecting said lever to said bracketand a spring connecting said lever to said brush; as set forth.

In testimon whereof, I afiix my signature in presence 0 two witnesses.

ALBERT AICHELE.

Witnesses CARL GUBLER, AUGUST Rinses.

